True Statement:
Brass has excellent corrosion resistance.

Explanation:


Corrosion resistance refers to the ability of a material to resist degradation and deterioration caused by chemical reactions with its surroundings, such as moisture or other corrosive substances. In the case of brass, it exhibits excellent corrosion resistance, making it a highly suitable material for various applications.

Composition and Properties of Brass:


Brass is an alloy composed primarily of copper (Cu) and zinc (Zn). The proportion of these elements can vary, resulting in different types of brass with varying properties. The addition of zinc to copper imparts several desirable properties to brass, including improved corrosion resistance.

Corrosion Resistance of Brass:


Brass exhibits excellent corrosion resistance due to the formation of a protective layer on its surface. When brass is exposed to air or moisture, a thin layer of corrosion products, known as a patina, forms on its surface. This patina acts as a barrier, preventing further corrosion and protecting the underlying material.

The corrosion resistance of brass is particularly beneficial in environments where exposure to moisture or corrosive substances is common. It makes brass a popular choice for applications such as plumbing fittings, valves, marine components, and musical instruments.

Other Properties of Brass:


While the other statements provided in the options are not true, it is important to mention them for clarity:

1. Cost: Brass is generally more cost-effective than copper. The addition of zinc to copper reduces the overall cost of the material while providing additional beneficial properties.
2. Machinability: Brass is known for its excellent machinability. It can be easily shaped, drilled, and machined into various complex forms, making it suitable for manufacturing processes.
3. Thermal Conductivity: Brass has good thermal conductivity, meaning it can efficiently transfer heat. This property makes it useful in applications such as heat exchangers and radiator cores.

In summary, while brass is cost-effective, has excellent machinability, and good thermal conductivity, the true statement among the options provided is that brass has excellent corrosion resistance.